In Greek mythology, Alpheus was the river god of the eponymous river, the modern-day Alfeios River in Greece. He was the son of the TitansOceanus and Tethys, and he married Telegone, with whom he had a son, King Orsilochus.

He was an avid hunter and fell in love with the nymph Arethusa. However, she managed to evade him and went to the island of Ortygia, where she turned into a well. Alpheus then transformed himself into a river and flowing under the Peloponnese all the way to Ortygia, he was able to reunite with her. According to a different myth, Alpheus fell in love with the goddess Artemis, whom he pursued, but she managed to evade him by covering her face in mud. Finally, in the story of the Twelve Labours of Heracles, the mythical hero rerouted the flow of the river Alpheus, so that it would pass through the Augean Stables to clean them from the filth in one day.